Calcium carbonate powder is used as a reinforcing filler for curable organopolysiloxane compositions and is frequently used as a reinforcing filler for condensation reaction-curing organopolysiloxane compositions. A large number of calcium carbonate powder-filled curable organopolysiloxane compositions of this type are known. For example, Japanese Laid Open (Kokai or Unexamined) Patent Application Number Hei 3-17158 (17,158/1991) discloses a room temperature-curing organopolysiloxane composition filled with calcium carbonate powder whose surface has been treated with rosin acid. Japanese Laid Open (Kokai or Unexamined) Patent Application Number Hei 3-56581 (56,581/1991) discloses a two-package silicone sealant composition filled with calcium carbonate powder whose surface has been treated with the ester of a fatty acid.
The aforementioned compositions, however, are poorly adhesive to a variety of substrates, such as glasses, plastics, and metals, and give cured products that will gradually delaminate from the adherend during long-term standing under severe conditions such as immersion in hot water.
The object of the present invention is to provide a curable organopolysiloxane composition which can generate a cured product that is strongly adhesive to substrates such as glasses, plastics, and metals and that exhibits a very durable adhesion in which adhesiveness is maintained even under severe conditions such as immersion in hot water.